The NIH/NCRR sponsored breeding programs of the National Primate Research Centers commonly house rhesus macaques in multimale-multifemale social groups in large outdoor corrals. This breeding program aims to develop cost-effective methods for enhancing reproduction to increase the number of monkeys available for research and to provide appropriate socialization for their psychological well-being. Although these outdoor corrals simulate natural social and environmental features, one of the most difficult problems in managing socially-housed macaques is their propensity for deleterious aggression. From a management perspective, such aggression is undoubtedly the most problematic behavior observed in group-housed rhesus macaques which can readily escalate to the degree that it results in serious physical trauma, lower reproductive performance and reduced psychological well-being. For over three years we have been conducting an NIH-funded R24 study using social network analysis to examine the internal (e.g. group composition, personality and temperament) and external (e.g., management factors) that influence rates of deleterious aggression and wounding in group-housed rhesus macaques. Our research has provided strong evidence that individual, family and group characteristics such as temperament, family structure and sex ratio interact to influence network structures such as patterns of submission, reconciliation, grooming and conflict intervention that are indicative of group stability and consequent deleterious aggression and wounding in captive rhesus macaques. The goal of this competitive renewal is to actively apply these results, which delineates three major pathways for reducing deleterious aggression/wounding in rhesus groups, to implement a series of perturbations that will experimentally test our correlational findings. Experimental perturbation of the pathways most important to reducing social instability will be conducted to causally validate which pathways are critical for group stability. This validation will allow us to advise colony managers at NPRCs and other primate facilities to use active and adaptive approach to management to reduce deleterious aggression and prevent severe outbreaks in arouo-housed rhesus macaques. PUBLIC HEALTH RELEVANCE (provided by applicant): This study will advance the current understanding of deleterious aggression in captive nonhuman primates using an experimental social network approach that will allow the development of an adaptive management program for primate facilities that will enhance group stability and successfully reduce deleterious aggression and prevent severe outbreaks in group-housed rhesus macaques. Rhesus macaques are an important biomedical model for human health research so this research is relevant by addressing the 3R's.